An optical pumping magnetic field measuring apparatus utilizing magnetic field optical properties of an alkali metal excited by optical pumping, uses as a sensor a glass cell in which an alkali metal gas (for example, potassium, rubidium, cesium or the like) is sealed. During magnetic field measurement, a static magnetic field is applied to this glass cell, and an energy level of the alkali metal in the glass cell is split by the Zeeman effect. Further, during magnetic field measurement, the optical pumping magnetic field measuring apparatus inputs a polarized light (for example, linearly polarized light, circularly polarized light or elliptically polarized light) or a modulated light (intensity-modulated light or phase-modulated light) into the glass cell while the static magnetic field is applied to the glass cell. Then, as a result of the light input, the optical pumping magnetic field measuring apparatus detects a magnetic field in the glass cell by using a spin state of the alkali metal caused in the glass cell.
As a technology related to the optical pumping magnetic field measuring apparatus, a technology described in Patent Document 1 is disclosed. The technology described in Patent Document 1 is to spin polarize the alkali metal in the glass cell by pump light (circularly polarized light) and to detect the magnetic field entering the glass cell by a rotation angle of polarization plane of a probe light (linearly polarized light) inputted into the glass cell in a direction perpendicular to the pump light.
Further, as the technology related to the optical pumping magnetic field measuring apparatus, a technology described in Patent Document 2 is disclosed. The technology described in Patent Document 2 is to spin polarize the alkali metal in the glass cell by the pump light (circularly polarized light), to generate magnetic resonance in the glass cell by applying an RF (a Radio Frequency) magnetic field to the glass cell, and to detect the ouogneiic field entering the glass cell by the pump light transmitted through the glass cell.
Further, as the technology related to the optical pumping magnetic field measuring apparatus, a technology described in Patent Document 3 is disclosed. The technology described in Patent Document 3 is to cause an electromagnetically induced transparency phenomenon in the alkali metal in the glass cell by a laser beam and to detect the magnetic field entering the glass cell by drive frequency of a light source for causing the electromagnetically induced transparency phenomenon.
Furthermore, as the technology related to the optical pumping magnetic field measuring apparatus, a technology described in Patent Document 4 is disclosed. The technology described in Patent Document 4 is to detect the magnetic field entering the glass cell by using magnetic resonance generated in the RF magnetic field in the same manner as the technology described in Patent Document 2, and to eliminate noises derived from the light source by calculating a difference between lights having passed through two glass cells.